Electric cable and apparatus for manufacturing it



Nov. 10, 1936.

H. J. BOE

ELECTRIC CABLE AND APPARATUS FOR MANUFACTURING IT 2 Sheets-Sheet 2 Filed June 30, 1932 INVENTOR fifimmm A TTORNEY Patented Nov. 10, 1936 UNITED" STATES PATENT OFFICE ELECTRIC CABLE AND APPARATUS FOR MANUFACTURING IT Application June 30, 1932, Serial No. 620,120

10 Claims.

This invention relates to an electric conducting system and apparatus for 'making it. and more particularly to a concentric conductor system for transmitting with small attenuation a band of frequencies whose upper limit extends well above the frequencies now employed in carrier transmission. v

It has been proposed in one instance to manufacture a concentric conductor system by employing a spiral insulating arrangement comprising a series of spokes passed transversely through the inner conductor and arranged spirally along the inner conductor with their outer ends acting as supports for the outer conductor for insulating the two conductors from each other, and

in other instances to employ concentric conductors each formed of tubing or into the general shape of the metallic tape employed for protecting the so-called B. X. cable and separated from each other by'spaced washers or a formed strip 'of generally helical configuration.

Objects of the invention are to provide an improved coaxial conductor system for high frequency transmission and apparatus for form- 25 ing the conductor system in which one of the conductors acts as a return for the other.

According to one embodiment of the invention herein shown and described the coaxial conductor pair have a substantially air dielectric there- 30 between, the inner conductor has slotted washers of insulating material spaced thereon, with the radial direction of the slots in successive washers rotating about the inner conductor, and which grip the inner conductor firmly and the outer 35 conductor encloses the inner conductor and is supported by the washers.

The invention may be better understood by reference to the following detailed description and accompanyingdrawings, in which- 40 Fig. 1 is a transverse sectional view of a group of conducting systems in accordance with one embodiment of the invention arranged in the form of a cable;

Fig. 2 is a plan view of one of the insulating 45 discs employed in the conducting systems;

Fig. 3 is a transverse sectional view of a group a! conducting systems in accordance with another embodiment of the invention arranged in the form of a cable;

Pig. 4 is a perspective view of a portion of one (I the conducting systems shown in Fig. 1;

\ I'ig. 5 is a perspective view of a portion of one oi the conducting systems shown in Fig. 3;

Hg. 0 is a section on the line 66 of Fig. 7;

55 Hg. 7 is a View in side elevation, partially in cross-section, of an apparatus for constructing the conducting systems shown in Figs. 1 and 4; Fig. 8 is a vertical sectional view on the line 88 of Fig. '7, and

Fig. 9 is a view in side elevation, partially in cross-section, of an apparatus for constructing the conducting systems shown in Figs. 3 and 5.

In a preferred embodiment of a conducting system, as shown in Figs. 1, 2 and 4, each of the concentric conductor systems l0 comprises an 10 inner conductor I l, a plurality of slotted discs or washers of elastically deformable insulating material assembled over the inner conductor ll so that each disc grips the inner conductor ll firmly, with the discs in widely spaced relation 15 and with the radial direction of the slots 2| rotating about the inner conductor ll. Around the spaced insulating discs 20 is assembled an enclosing outer conductor preferably comprising a plurality of wavy conducting wires [3 held in 20 place by suitable binding means 44 to form a cylinder having the same axis as the central conductor. A plurality of the concentric conductor systems I0 are assembled together and held in place by suitable binding means l6 over which is applied an outer protective covering H which may comprise a sheath of lead extruded over the assembled group, or rubber, gutta percha or other suitable material continuously applied over the assembled group.

In order that the attenuation may be made small at high frequencies, the leakage loss between the conductors must be as small as possible. As the leakage loss is due to the dielectric interposed between the conductors the principal volume constituent of the dielectric should be air since air produces no leakage loss. Accordingly, the spaced insulating washers 20 which maintain the inner conductor H and the wavy wires I3, comprising the outer conductor, in concentric relation and out of electrical contact with each other should be separated from each other by suitable distances and should be made as thin as possible consistent with required mechanical strength. They are composed of material having a small loss angle and low dielectric constant in order to make the leakage loss as small as possible. The insulating discs or washers 20 are constructed as shown in Fig. 2 with a circular hole therein of a size such that the washor will firmly grip the inner conductor H and a slot 2| slightly narrower than the diameter of the circular hole. With this construction the washer 20, after having been sprung into place over the inner conductor ll, cannot be readily displaced therefrom. Hence the washers are made of an elastically deformable insulating material, in order to be sprung over the inner conductor and to grip it elastically and firmly.

In a preferred embodiment of apparatus as shown in Figs. 6, '1 and 8, for forming the concentric conducting system shown in Figs. 1 and 4, a supply reel 55 containing a length of inner conductor II is mounted on a supporting bracket 5|. A mechanism 52 (Figs. '7 and 8) is' provided 'for applying the insulating discs or washers 25 intermittently at predetermined intervals on the inner conductor so that the discs 25 grip the conductor firmly and the radial directions of successive slots 2| rotate about the conductor II.

In the embodiment illustrated in Fig. 8 the discs 25 are applied with the slots'extending in three different directions although it is also within the scope of the invention to have the slots extending in two or inmore than three different directions. Three individual supply means or magazines 55, 54 and 55, each containing a supply of discs 25,- are arranged about the inner conductor ll. Each of the supply means is arranged so that the discs will be forced toward an opening 55 therein and each has a spring controlled plunger 51 for forcing the discs 25 into position on the wire A cam arrangement 55 is provided to force the plunger 51 toward the wire against the tension of the springs 55. The cam arrangement 55 is arranged to rotate so that the discs 25 are ejected from the supply 'and a connecting rod 55 attached to the crank 55 and to the distributing plate 52 are provided to give 'an oscillating movement to the distributing plate 52 when the gear 51 is rotated. A sizing dieor polisher 55 is provided having a cone shaped opening 15 at one end to properly assemble the wires l5 over the insulating discs 25. The serving head 1| having a rotating binder supply 12 carrying a supply of binders 55 is 'prov'ided to suitably bind the inner and outer conductors with their associated discs.

A capstan 15 is provided to pull the inner conductor, the wires forming the outer conductor, and the assembled conducting system through the apparatus after which it may be accumulated on a take-up reel 15.

A suitable source of power such as a motor 15, and suitable connecting transmission elements are provided to drive the cam 55 for applying the discs to the inner conductor, the gears 51 for oscillating the distributing plate 52, the supply means 12 around the concentric conducting system, the capstan 15 and the take-up reel 15. r

The operation of the system shown in Figs. 6, 7 and 8 is as follows: As the motor 15 rotates the capstan 15 and the take-up reel 15, the inner conductor II is drawn from the s pp y reel 55 and the wires II are drawn from the supplies 55 through the apparatus. As the inner conductor II is drawn through the mechanism 52, the cam. 55 rotates and forces the discs 25 from the supply means 55, 54 and 55, in succession. As the conductor H with the discs 25 assembled thereon, and the wires ii, are drawn through the distributing plate 52 and the sizing die 55, the oscillating movement of the distributing plate 52 continuously changes the radial position of each of the wires I5 with respect to the inner conductor H which produces a wavy condition in the wires l5 as shown in Fig. 4. As the concentric conductor system passes through the remainder of the apparatus the rotation of the binder supply 12 applies the binder 44 and the assembled conducting system is wound onto the take-up reel 14.

In another preferred embodiment of a conducting system, as shown in Figs. 3 and 5, the inner conductor ll of each of the concentric conducting systems may comprise a cylindrical tube of a material easily flexed, such as lead tubing over which a coating of a suitable good conducting material such as copper or silver has been applied by electroplating or other suitable methods and the outer conductor 33 may comprise a cylindrical tube formed from a sheet or tape of material easily flexed such as lead and having a coating of a suitable conducting material such as copper or silver applied to the inner surface by electroplating or other suitable methods. The edges 54 of the sheet forming the outer conductor are arranged to abut and are secured together by soldering, brazing or other suitable methods to form a water-tight outer conductor. The insulating discs are arranged as described above in connection with the conducting system shown in Figs. 1 and 4,

Referring to Fig. 9 a preferred embodiment of apparatus for forming the concentric conducting system 55 shown in Figs. 3 and 5 is in general similar to that shown in Fig. '1. The supply reel 55 carrying a supply of inner conductor 5|, the mechanism 52 for applying the insulating discs 25 on the inner conductor 5| and the take-up reel 14 on which the concentric conducting system 55 is accumulated are the same as corresponding parts shown in Fig. 7.

A supply reel 55 containing a length of tape from which the outer conductor is formed is mounted beneath the inner conductor 5| with its associated discs 25. A forming roller 5| having a half round peripheral grove therein is positioned so that the inner conductor 5| and the discs 25 assembled thereon are forced against the central portion of the tape to form or curve the bottom or central portion thereof. Two sets of forming rollers and associated guides 52-45 and 5455 are provided with half round peripheral grooves therein to form the sides of the tape comprising the outer conductor 55 around the insulating discs 25.

A suitable mechanism 55 is provided to join the edges 55 of the outer conductor. The mechanism 55 may take the form of suitable soldering, brazing or welding apparatus to unite the edges 54 to form a water-tight joint. A capstan 51, preferably of the so-called endless belt or tractor type is provided to pull the inner conductor 5|, the outer conductor 53 and the assembled conducting system 55 through the apparatus. Suitable transmission elements are employed to connect the power source 15 with the mechanism 52, the capstan 51 and the take-up reel 15.

The operation of the system shown in Fig. 9 is as follows:

As the motor 15 drives the capstan 51 and the take-up reel 14, the inner conductor 5| is drawn from the supply reel 55 and the tape forming the outer conductor 33 is drawn from the supply reel 80 through the apparatus. As the inner conductor 3| is drawn through the mechanism 52 the discs 20 are assembled thereon as described above in connection with Fig. '7. As the conductor 3| with the discs 20 assembled thereon and the tape from the supply reel 80 which forms the outer conductor 33 are drawn through the forming apparatus 8|, 82, 83, 84 and 85, the tape is formed around the inner conductor and insulating discs and takes the form shown in Figs. 3 and 5. As the conducting system is drawn through the apparatus 86 the edges 34 are heated, melted and subsequently upon solidification fuse together to form a water-tight joint.

It is to be understood that the invention is not to be limited to the particular embodiment shown, nor to the particular arrangements that have been described and shown in detail but only by the scope of the appended claims.

What is claimed is:

1. A coaxial conduct-or pair having air as the principal volume constituent of the dielectric between the conductors, comprising an inner conductor, a plurality of thin discs of elastically deformable insulating material and each having a radial slot therein and elastically gripping the inner conductor between the walls ofsuch slot to resist longitudinal displacement on the conductor, the radial slots of successive washers extending out from the. inner conductor in difierent directions and the discs being widely spaced along the inner conductor, and an enveloping outer conductor applied over the outer edges of the discs and thereby spaced coaxially from the inner conductor.

2. In ,an apparatus for making a flexible concentric conductor having a dielectric which is substantially air, means for continuously advancing an inner conductor, means for automatically pressing onto said inner conductor at predetermined intervals from different radial directions, slotted insulating discs having a central hole so that the discs grip the inner conductor firmly, the sides ofthe holes in the discs are perpendicular to the inner conductor and the slots in successive discs extend at different radial directions from the inner conductor, and means for assembling an outer conductor comprising a plurality of conducting elements parallel to each other around and in contact with the spaced insulating discs, comprising a rotatably mounted distributing plate having an aperture through which the inner conductor and the assembled discs is adapted to pass and a plurality of apertures through which the conducting elements forming the outer conductor are adapted to pass, and means for oscillating said distributing plate.

3. In an apparatus for making a coaxial conductor pair having air as the principal volume constituent of the dielectric between the conductors, means to continually advance an inner conductor, means to spring radially slotted thin dlscsof elastically deformable insulating material over the inner conductor at widely spaced intervals along the conductor to grip the conductor between the walls of the slots to resist longitudiml displacement of the discs on the conductor, the discs being sprung over the conductor in successive difierent radial directions thereto whereby successive discs stand on the conductor with the radial slots of the discs extending from the conductor in difierent directions, and means to continuously longitudinally wave and apply a plurality of wires over the outer edges of the discs to form an outer conductor coaxially spaced from the inner conductor by the discs.

4. In an apparatus for making a flexible concentric conductor pair having air as the prin-' cipal volume constituent of the dielectric between the conductors, means for continuously advancing an inner conductor, means to place radially slotted thin discs of elastically deformable insulating material intermittently on the inner conductor at widely spaced intervals along the conductor, and means to apply an outer coaxial conductor over the outer edges of the discs, the said means to set the discs on the inner conductor comprising a plurality of stationary magazines radially disposed around the advancing conductor and adapted to present successive discs to the conductor from successively differing direc tions and with the radial slots of the discs directed toward the conductor, and means to push and thereby spring the successive discs over the conductor to stand thereon perpendicularly thereto with the radial slots of successive discs extending from the conductor in different directions and with the conductor firmly gripped between the walls of the slots.

5. In an apparatus for making electrical conductors, means for continually advancing a conductor, and means for placing radially slotted discs on the conductor comprising a plurality of magazines arranged in different radial directions around the conductor and each having means to present discs successively to the conductor, and means to press the discs thus presented into position on the conductor with the conductor between the walls of the slots in the discs.

6. In an apparatus for making electrical conductors, means for continually advancing a conductor, and means for placing radially slotted discs on the conductor comprising a plurality of magazines arranged in difierent radial directions around the conductor and each having means to present discs successively to the conductor, and means to press the discs thus presented into position on the conductor with the conductor between the walls 01' the slots in the discs, the last named means including a plunger in each magazine and a rotating cam to operate the plungers in succession.

'7. In an apparatus for making a coaxial conductor pair having air as the principal volume constituent of the dielectric between the conductors, means to advance an inner conductor, means to spring radially slotted thin discs of elastically deformable insulating material over I the inner conductor at widely spaced intervals along the conductor to grip the conductor between the walls of the slots to resist'longitudinal displacement of the discs on the conductor, the discs being sprung over the conductor in successive different radial directions thereto whereby successive discs stand on the conductor with the radial slots of the discs extending from the conductor in different directions, and means to longitudinally wave and apply a plurality of wires over the outer edges of the discs to form an outer conductor coaxially spaced from the inner conductor by the discs.

8. In an apparatus for making a flexible concentric conductor pair having air as the principal volume constituent of the dielectric between the conductors, means ,for advancing an inner widely spaced intervals along the conductor, and means to apply an outer coaxial conductor over the outer edges oi the discs, the said means to set the discs on the inner conductor comprising a plurality of stationary magazines radially disposed around the advancing conductor and adapted to present successive discs to the conductor from successively diifering directions and with the radial slots of the discs directed toward the conductor, and means to push and thereby spring the successive discs over the conductor to stand thereon perpendicularly thereto with the radial slots of successive discs extending Irom the conductor in difl'erent directions and with the conductor firmly gripped between the walls of the slots.

9. In an apparatus for making electrical conductors, means for advancing a conductor, and means for placing-radially slotted discs on the conductor comprising a plurality of magazines arranged in different radial directions around the conductor and each having means to present discs successively to the conductor, and means to press the discs thus presented into position on the conductor with the conductor between the walls 01' the-slots in the discs.

10'. apparatus for making electrical conductors, means for advancing a conductor, and means for placing radially slotted discs on the conductor comprising a plurality of magazines arranged in diilerent radial directions around the conductor and each having means to present discs successively to the conductor, and means to press the discs thus presented into position on the conductor with the conductor between the walls of the slots in the discs, the last named means including a plunger in each magazine and a rotating cam to operate the plungers in succession.

HELMER J. BOE. 

